Agri-Food & Biosciences Institute

Annual Report Marine Biotoxin Analysis Official Control Monitoring Programme For Northern Ireland 1st January 2019 – 31st December 2019

Final Version 28/02/2020

Contract Reference: FS515003

9 pages

Quality statement: This report is a compilation of the information included on the reports provided weekly/monthly to the FSANI and showing the results of the toxin analyses undertaken on samples submitted by third parties. All results were quality checked and approved prior to release to the FSANI and the results compiled in this report have been further checked against a copy of the original reports held on a central database. Information relating to the origin of the samples (place, date and time of collection) is as provided by sampling staff and has not undergone verification checks by AFBI. Method Standard Operating Procedures used during the course of the programme:

Determination of Domoic Acid in Shellfish by High Performance Liquid Chromatography (CSD 406)

Determination of Paralytic Shellfish Poison by High Performance Liquid Chromatography (CSD 408)

Determination of Lipophilic Toxins in Shellfish Species by LC-MS/MS (CSD 379)

Results of Programme

Table 1: Monitoring Samples Received 2019

| Sample Type | Number of samples | |-------------|-------------------| | Oyster | 134 | | Mussel | 326 | | Total number of samples | 460 |

Table 2: Tests Carried Out 2019

| Test | Oyster | Mussel | Total | |-----------------|--------|--------|-------| | Domoic Acid | 129 | 316 | 445 | | PSP | 129 | 315 | 444 | | Lipophilic Toxins | 134 | 325 | 459 | | Total number of tests | 1348 |

Table 3: Positive Northern Ireland Monitoring Samples 2019 (Levels above the regulatory limits)

| Test | Oyster | Mussel | Total | |-----------------|--------|--------|-------| | Domoic Acid | 0 | 0 | 0 | | PSP | 0 | 0 | 0 | | Lipophilic Toxins | 0 | 4 | 4 | | Total number of positive tests | 4 | Table 4: Turn Round Times 2019

| Test | Target | Percentage within Target | |-----------------------|--------------|--------------------------| | Domoic Acid | 95% in 3 Days| 100% | | PSP | 95% in 3 Days| 100% | | Lipophilic Toxins | 95% in 3 Days| 100% |

Table 5: Overview of the toxin results obtained for each bed monitored in 2019 within NI classified production areas

| Site location | Site Identification Reference (SIR) | No of samples received | Shellfish Species | DSP OA/DTX/PTX (µg/kg) | DSP AZA (µg/kg) | DSP YTX (mg/kg) | PSP (µg/kg) | ASP (µg/g) | |---------------------|-------------------------------------|------------------------|-------------------|------------------------|----------------|----------------|-------------|------------| | Belfast Lough | B1-AFFNI 55 | 51 | Mussel | 65 | NEG | NEG | NEG | \<0.3 | | Belfast Lough | B3-AFFNI 50 | 51 | Mussel | 135 | NEG | NEG | NEG | 1.2 | | Belfast Lough | B12-AFFNI 54 | 51 | Mussel | 155 | NEG | NEG | NEG | 1.6 | | Belfast Lough | B20-AFFNI 53 | 51 | Mussel | 134 | NEG | NEG | NEG | 0.5 | | Carlingford Lough | C1-AFFNI 27 | 13 | Mussel | NEG | NEG | NEG | NEG | \<0.3 | | Carlingford Lough | C11-AFFNI 84 | 13 | Oyster | 63 | NEG | NEG | NEG | 0.32 | | Carlingford Lough | C15-AFFNI 89 | 12 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Carlingford Lough | C17-AFFNI 92 | 11 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Carlingford Lough | C7-AFFNI 73 | 13 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Carlingford Lough | C9-AFFNI 39 | 11 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Carlingford Lough | NW-Wild Fishery | 13 | Mussel | NEG | NEG | NEG | NEG | \<0.3 | | Dundrum Bay | DB1-AFFNI 95A | 14 | Oyster | 30 | NEG | NEG | NEG | \<0.3 | | Dundrum Bay | DB1-AFFNI 95A | 17 | Mussel | 261 | NEG | NEG | NEG | \<0.3 | | Dundrum Bay | DB2-AFFNI 95B | 13 | Mussel | 170 | NEG | NEG | NEG | 0.74 | | Killough | K1-AFFNI 18 | 6 | Mussel | 43 | NEG | NEG | NEG | \<0.3 | | Killough | K1-AFFNI 18 | 13 | Oyster | 11 | NEG | NEG | NEG | 0.54 | | Larne Lough | L5-AFFNI 21B | 10 | Mussel | NEG | NEG | NEG | NEG | \<0.3 | | Larne Lough | L5-AFFNI 21B | 10 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Larne Lough | L3-AFFNI 88 | 12 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Lough Foyle | PA3M-Wild Fishery | 12 | Mussel | NEG | NEG | NEG | NEG | \<0.3 | | Lough Foyle | PA3O-Wild Fishery | 5 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Lough Foyle | PA4M-Wild Fishery | 12 | Mussel | NEG | NEG | NEG | NEG | \<0.3 | | Lough Foyle | PA4O- Wild Fishery | 5 | Oyster | NEG | NEG | NEG | NEG | \<0.3 | | Strangford Lough | S7-AFFNI 76 | 12 | Mussel | NEG | NEG | NEG | NEG | \<0.3 | | Strangford Lough | S7-AFFNI 76 | 15 | Oyster | NEG | NEG | NEG | NEG | 0.33 | | Strangford Lough | S2-AFFNI 42 | 14 | Mussel | 60 | NEG | NEG | NEG | \<0.3 | Proficiency Test Results for Methods used for Official Control Purposes in 2019

Performance in proficiency tests is assessed using a Z-score. This is calculated for each participant’s data. Each sample /matrix combination is given an assigned value and Z-score is calculated thus:

[ Z\\text{-score} = \\frac{\\text{Mean from Laboratory} - \\text{Assigned Value}}{\\text{Total Error}} ]

The total error is based on values set for the proportional error and the constant error. These values are set by the organisers. The numbers in the z column indicate:

- (|Z| < 2) satisfactory performance
- (2 < |Z| < 3) questionable performance
- (|Z| > 3) unsatisfactory performance

Domoic Acid 2019 Proficiency Test Summaries

Table 6: EURL 2019 - HPLC

| Sample ID | Sample description | Assigned value | Reported value | Units | z-score | |-----------------|--------------------------|----------------|----------------|-------|---------| | EURLMB/19/A/01 | Shellfish homogenate | 7.3 | 7.2 | mg/kg | -0.10 | | EURLMB/19/A/02 | Shellfish homogenate | 76.5 | 77.9 | mg/kg | 0.10 |

Table 7: Quasimeme Round 2019.1 - HPLC

| Sample ID | Sample description | Assigned value | Reported value | Units | z-score | |-----------------|--------------------------|----------------|----------------|-------|---------| | QST260BT | Scallop tissue | 27 | 26 | mg/kg | -0.29 | | QST261BT | Queen scallop adductor muscle | 28.1 | 29.5 | mg/kg | 0.39 | | QST262BT | Pacific oyster | 8.4 | 8.3 | mg/kg | -0.09 |

Table 8: Quasimeme Round 2019.2 - HPLC

| Sample ID | Sample description | Assigned value | Reported value | Units | z-score | |-----------------|--------------------------|----------------|----------------|-------|---------| | QST269BT | Oyster tissue | 17.1 | 18.7 | mg/kg | 0.7 | | QST270BT | Queen scallop adductor muscle | 28.3 | 32.2 | mg/kg | 1.1 | | QST271BT | Blue mussel | 52.1 | 45.9 | mg/kg | -0.9 |

### Table 9: EURL 2019 - HPLC

| Sample ID | Matrix | Determinant | Assigned Value | Reported Value | Units | z-Score | |-------------|-------------------------|-------------|----------------|----------------|---------------------|---------| | EURLMB/19/P/01 | Shellfish homogenate | Total toxicity | 967 | 1346 | µgSTX2HCL eq./kg | 2.40 | | EURLMB/19/P/01 | Shellfish homogenate | dcGTX-2,3 | 82.3 | 135.8 | µgSTX2HCL eq./kg | 2.50 | | EURLMB/19/P/01 | Shellfish homogenate | dcSTX | 642.8 | 908.7 | µgSTX2HCL eq./kg | 2.20 | | EURLMB/19/P/01 | Shellfish homogenate | GTX-2,3 | 137.4 | 251.7 | µgSTX2HCL eq./kg | 3.50 | | EURLMB/19/P/01 | Shellfish homogenate | GTX-5 | 3.4 | ND | µgSTX2HCL eq./kg | | | EURLMB/19/P/01 | Shellfish homogenate | STX | 24.4 | 17.9 | µgSTX2HCL eq./kg | -1.10 | | EURLMB/19/P/01 | Shellfish homogenate | dcNEO | 58.4 | ND | µgSTX2HCL eq./kg | | | EURLMB/19/P/01 | Shellfish homogenate | GTX-6 | 25.8 | 31.6 | µgSTX2HCL eq./kg | 0.90 | | EURLMB/19/P/02 | Shellfish homogenate | Total toxicity | 1026.0 | 1312.0 | µgSTX2HCL eq./kg | 1.60 | | EURLMB/19/P/02 | Shellfish homogenate | C-1,2 | 149.5 | 231.9 | µgSTX2HCL eq./kg | 2.40 | | EURLMB/19/P/02 | Shellfish homogenate | dcSTX | 274.2 | 364.5 | µgSTX2HCL eq./kg | 1.60 | | EURLMB/19/P/02 | Shellfish homogenate | GTX-2,3 | 53.0 | 78.5 | µgSTX2HCL eq./kg | 1.90 | | EURLMB/19/P/02 | Shellfish homogenate | GTX-5 | 194.2 | 232.5 | µgSTX2HCL eq./kg | 0.90 | | EURLMB/19/P/02 | Shellfish homogenate | dcNEO | 36.7 | ND | µgSTX2HCL eq./kg | | | EURLMB/19/P/02 | Shellfish homogenate | C-3,4 | 59.7 | 81.1 | µgSTX2HCL eq./kg | 1.30 | | EURLMB/19/P/02 | Shellfish homogenate | GTX-6 | 147.8 | 173.6 | µgSTX2HCL eq./kg | | | EURLMB/19/P/03 | Shellfish homogenate | Total toxicity | 645.0 | 788.0 | µgSTX2HCL eq./kg | 1.20 | | EURLMB/19/P/03 | Shellfish homogenate | GTX-2,3 | 358.2 | 511.6 | µgSTX2HCL eq./kg | 2.20 | | EURLMB/19/P/03 | Shellfish homogenate | STX | 253.7 | 276.2 | µgSTX2HCL eq./kg | 0.50 |

### Table 10: Quasimeme Round 2019.1 - HPLC

| Sample ID | Sample description | Determinant | Assigned Value | Reported Value | Units | z-score | |-----------|--------------------|-------------|----------------|----------------|---------------------|---------| | QST 266BT | Mussel tissue | GTX-2,3 | 3.21 | 3.04 | µmol/kg | -0.37 | | QST 266BT | Mussel tissue | STX | 1.74 | 1.57 | µmol/kg | -0.62 | | QST 266BT | Mussel tissue | Total toxicity | 1334 | 1263 | µgSTXdiHCl eq./kg | -0.42 | | QST 267BT | Mussel tissue | GTX-2,3 | 2.94 | 2.77 | µmol/kg | -0.38 | | QST 267BT | Mussel tissue | STX | 1.41 | 1.3 | µmol/kg | -0.48 | | QST 267BT | Mussel tissue | Total toxicity | 1156 | 1101 | µgSTXdiHCl eq./kg | -0.37 | | QST 268BT | Mussel tissue | dc-Neo | 0.21 | 0.26 | µmol/kg | 0.48 | | QST 268BT | Mussel tissue | dc-STX | 1.87 | 1.38 | µmol/kg | -1.54 | | QST 268BT | Mussel tissue | GTX-2,3 | 0.07 | 0.07 | µmol/kg | 0.00 | | QST 268BT | Mussel tissue | STX | 0.08 | 0.06 | µmol/kg | -0.33 | | QST 268BT | Mussel tissue | Total toxicity | 762.4 | 592 | µgSTXdiHCl eq./kg | -1.54 |

### Table 11: Quasimeme Round 2019.2 - HPLC

| Sample ID | Sample description | Determinant | Assigned Value | Reported Value | Units | z-score | |-----------|--------------------|-------------|----------------|----------------|-------|---------| | QST275BT | Mussel tissue | GTX-2,3 | 5.02 | 4.56 | µmol/kg | -0.5 | | QST275BT | Mussel tissue | STX | 3.4 | 3.24 | µmol/kg | -0.3 | | QST275BT | Mussel tissue | Total toxicity | 2327 | 2224 | µgSTXdiHCleq./kg | -0.3 | | QST276BT | Mussel tissue | dc-STX | 0.51 | 0.44 | µmol/kg | -0.6 | | QST276BT | Mussel tissue | GTX-2,3 | 5.35 | 4.98 | µmol/kg | -0.4 | | QST276BT | Mussel tissue | STX | 1.27 | 1.11 | µmol/kg | -0.7 | | QST276BT | Mussel tissue | Total toxicity | 1768 | 1689 | µgSTXdiHCleq./kg | -0.3 | | QST277BT | Mussel tissue | GTX-2,3 | 6.85 | 6.26 | µmol/kg | -0.5 | | QST277BT | Mussel tissue | STX | 1.88 | 1.66 | µmol/kg | -0.7 | | QST277BT | Mussel tissue | Total toxicity | 2163 | 2012 | µgSTXdiHCleq./kg | -0.5 |

### Lipophilic Toxins 2019 Proficiency Test Summaries

### Table 12: EU RL 2019 - LC-MS/MS

| Sample ID | Matrix | Determinant | Assigned Value | Reported Value | Units | z-score | |-----------|--------|-------------|----------------|----------------|-------|---------| | EU RLMB/19/L/01 | Mussel homogenate | Total OA group | 1659.5 | 1435.8 | µg OA eq./kg | -0.80 | | EU RLMB/19/L/01 | Mussel homogenate | Free OA | 200.6 | 150.0 | µg/kg | -1.20 | | EU RLMB/19/L/01 | Mussel homogenate | Free DTX2 | 165.0 | 123.0 | µg/kg | -1.10 | | EU RLMB/19/L/01 | Mussel homogenate | Total OA | 1418.8 | 1266.0 | µg/kg | -0.70 | | EU RLMB/19/L/01 | Mussel homogenate | Total DTX2 | 330.2 | 283.0 | µg/kg | -0.80 | | EU RLMB/19/L/01 | Mussel homogenate | Total YTX | 3.0 | 3.0 | mg YTX eq./kg | 0.10 | | EU RLMB/19/L/01 | Mussel homogenate | YTX | 0.2 | 0.2 | mg/kg | 0.00 | | EU RLMB/19/L/01 | Mussel homogenate | homo-YTX | 2.1 | 1.9 | mg/kg | -0.50 | | EU RLMB/19/L/01 | Mussel homogenate | 45 OH YTX | 0.3 | 0.2 | mg/kg | -0.80 | | EU RLMB/19/L/01 | Mussel homogenate | 45 OH homo YTX | 1.2 | 1.5 | mg/kg | 1.40 | | EU RLMB/19/L/02 | Mussel homogenate | Total OA group | 82.1 | 47.2 | µg OA eq./kg | -1.90 | | EU RLMB/19/L/02 | Mussel homogenate | Free OA | 43.5 | 27.8 | µg/kg | -1.60 | | EU RLMB/19/L/02 | Mussel homogenate | Total OA | 80.7 | 47.2 | µg/kg | -1.80 | | EU RLMB/19/L/02 | Mussel homogenate | AZA group | 476.5 | 451.3 | µg AZA eq./kg | -0.30 | | EU RLMB/19/L/02 | Mussel homogenate | AZA1 | 262.2 | 253.0 | µg/kg | -0.20 | | EU RLMB/19/L/02 | Mussel homogenate | AZA2 | 73.8 | 74.1 | µg/kg | 0.00 | | EU RLMB/19/L/02 | Mussel homogenate | AZA3 | 55.2 | 46.4 | µg/kg | -0.70 | | EU RLMB/19/L/03 | Mussel homogenate | Total OA group | 904.9 | 877.4 | µg OA eq./kg | -0.20 | | EU RLMB/19/L/03 | Mussel homogenate | Free OA | 20.8 | 14.8 | µg/kg | -1.20 | | EU RLMB/19/L/03 | Mussel homogenate | Free DTX1 | 225.2 | 229 | µg/kg | 0.10 | | EU RLMB/19/L/03 | Mussel homogenate | Total OA | 49.4 | 23.4 | µg/kg | -2.10 | | EU RLMB/19/L/03 | Mussel homogenate | Total DTX1 | 787.7 | 854 | µg/kg | 0.40 | | Sample ID | Sample Description | Determinant | Assigned Value | Reported Value | Units | z-Score | |-----------|--------------------|-------------|----------------|----------------|-------|---------| | QST263BT | Mussel tissue | 45-OH-homo-YTX | 0.51 | 0.60 | mg/kg | 1.09 | | QST263BT | Mussel tissue | 45-OH-YTX | 0.12 | 0.15 | mg/kg | 1.17 | | QST263BT | Mussel tissue | AZA-1 | 737.7 | 639 | µg/kg | -1.06 | | QST263BT | Mussel tissue | AZA-2 | 209.6 | 217 | µg/kg | 0.28 | | QST263BT | Mussel tissue | AZA-3 | 124.7 | 110 | µg/kg | -0.91 | | QST263BT | Mussel tissue | AZA-total | 1303.6 | 1183 | µg AZA eq./kg | -0.73 | | QST263BT | Mussel tissue | Free-DTX1 | 85.8 | 71.2 | µg/kg | -1.27 | | QST263BT | Mussel tissue | Free-DTX2 | 567.2 | 520 | µg/kg | -0.65 | | QST263BT | Mussel tissue | free-Okadaic-Acid | 149.1 | 134 | µg/kg | -0.79 | | QST263BT | Mussel tissue | Homo-YTX | 1.1 | 1.04 | mg/kg | -0.37 | | QST263BT | Mussel tissue | Total OA group + PTX group | 904.1 | 804 | µg OA eq./kg | -0.87 | | QST263BT | Mussel tissue | Total DTX1 | 112.6 | 101 | µg/kg | -0.79 | | QST263BT | Mussel tissue | Total DTX2 | 786.6 | 690 | µg/kg | -0.95 | | QST263BT | Mussel tissue | Total-free-OA+DTX1+DTX2 | 562.9 | 517 | µg OA eq./kg | -0.63 | | QST263BT | Mussel tissue | Total-hy-OA+DTX1+DTX2 | 924.4 | 804 | µg OA eq./kg | -1.01 | | QST263BT | Mussel tissue | Total okadaic acid | 339.1 | 289 | µg/kg | -1.14 | | QST263BT | Mussel tissue | Total-YTX | 1.76 | 1.75 | mg YTX eq./kg | -0.03 | | QST263BT | Mussel tissue | YTX | 0.23 | 0.26 | mg/kg | 0.79 | | QST264BT | Mussel extract | AZA-1 | 97 | 87 | µg/kg | -0.77 | | QST264BT | Mussel extract | AZA-2 | 20.5 | 22.8 | µg/kg | 0.84 | | QST264BT | Mussel extract | AZA-3 | 36.8 | 32.3 | µg/kg | -0.93 | | QST264BT | Mussel extract | AZA-total | 187 | 173.6 | µg AZA eq./kg | -0.54 | | QST264BT | Mussel extract | Free-DTX2 | 3.9 | 3.6 | µg/kg | -0.50 | | QST264BT | Mussel extract | free-Okadaic-Acid | 38.7 | 37.9 | µg/kg | -0.16 | | QST264BT | Mussel extract | Total OA group + PTX group | 47.9 | 49.8 | µg OA eq./kg | 0.31 | | QST264BT | Mussel extract | Total-DTX2 | 4.1 | 3.4 | µg/kg | -1.20 | | QST264BT | Mussel extract | Total-free-OA+DTX1+DTX2 | 41.3 | 40 | µg OA eq./kg | -0.23 | | QST264BT | Mussel extract | Total-hy-OA+DTX1+DTX2 | 48.4 | 49.8 | µg OA eq./kg | 0.22 | | QST264BT | Mussel extract | Total-Okadaic-Acid | 46 | 47.7 | µg/kg | 0.29 | | QST265BT | Mussel | AZA-1 | 422.2 | 367 | µg/kg | -1.02 | | QST265BT | Mussel | AZA-2 | 118.6 | 130 | µg/kg | 0.75 | | QST265BT | Mussel | AZA-3 | 84.7 | 72.9 | µg/kg | -1.06 | | QST265BT | Mussel | AZA-total | 767.5 | 703 | µg AZA eq./kg | -0.66 | | QST265BT | Mussel | Free-DTX2 | 101.4 | 82.8 | µg/kg | -1.41 | | QST265BT | Mussel | free-Okadaic-Acid | 45.9 | 35.8 | µg/kg | -1.69 | | QST265BT | Mussel | Total-DTX2 | 148.5 | 119 | µg/kg | -1.44 | | QST265BT | Mussel | Total-free-OA+DTX1+DTX2 | 106.9 | 85.5 | µg OA eq./kg | -1.52 | | QST265BT | Mussel | Total-hy-OA+DTX1+DTX2 | 186.3 | 154.4 | µg OA eq./kg | -1.33 | | QST265BT | Mussel | Total-Okadaic-Acid | 99.1 | 83 | µg/kg | -1.23 | | Sample ID | Sample Description | Determinant | Assigned Value | Reported Value | Units | z-Score | |------------|--------------------|--------------------------------------------------|----------------|----------------|-------------|---------| | QST272BT | Mussel tissue | Free-DTX2 | 407 | 392.4 | µg/kg | -0.3 | | QST272BT | Mussel tissue | Free-Okadaic acid | 153 | 142.6 | µg/kg | -0.5 | | QST272BT | Mussel tissue | Total-free-OA+DTX1+DTX2 | 404 | 378.1 | µg OA eq./kg | -0.5 | | QST272BT | Mussel tissue | Total-DTX2 | 706 | 693.7 | µg/kg | -0.1 | | QST272BT | Mussel tissue | Total-Okadaic acid | 484 | 475.2 | µg/kg | -0.1 | | QST272BT | Mussel tissue | Total-hy-OA+DTX1+DTX2 | 920 | 891.4 | µg OA eq./kg | -0.2 | | QST272BT | Mussel tissue | Total OA group + PTX group | 924 | 891.4 | µg OA eq./kg | -0.3 | | QST273BT | Mussel extract | AZA-1 | 13.6 | 10.7 | µg/kg | -1.6 | | QST273BT | Mussel extract | AZA-2 | 3.87 | 3.5 | µg/kg | -0.7 | | QST273BT | Mussel extract | AZA-3 | 3.94 | 3.9 | µg/kg | -0.1 | | QST273BT | Mussel extract | AZA-total | 25.4 | 22.5 | µg AZA eq./kg | -0.9 | | QST273BT | Mussel extract | Free-DTX2 | 60.8 | 53.4 | µg/kg | -0.9 | | QST273BT | Mussel extract | Free-Okadaic Acid | 11.0 | 10.5 | µg/kg | -0.3 | | QST273BT | Mussel extract | Total-free-OA+DTX1+DTX2 | 49.4 | 42.5 | µg OA eq./kg | -1.1 | | QST273BT | Mussel extract | Total-DTX2 | 74.2 | 68.8 | µg/kg | -0.5 | | QST273BT | Mussel extract | Total-Okadaic Acid | 18.7 | 16.7 | µg/kg | -0.8 | | QST273BT | Mussel extract | Total-hy-OA+DTX1+DTX2 | 63.0 | 57.9 | µg OA eq./kg | -0.6 | | QST273BT | Mussel extract | Total OA group + PTX group | 64.4 | 57.9 | µg OA eq./kg | -0.8 | | QST273BT | Mussel extract | YTX | 0.031 | 0.031 | mg/kg | 0.0 | | QST273BT | Mussel extract | Homo-YTX | 0.302 | 0.328 | mg/kg | 0.5 | | QST273BT | Mussel extract | 45-OH-homo-YTX | 0.174 | 0.196 | mg/kg | 0.6 | | QST273BT | Mussel extract | 45-OH-YTX | 0.023 | 0.025 | mg/kg | 0.1 | | QST273BT | Mussel extract | Total-YTX | 0.432 | 0.481 | mg YTX eq./kg | 0.7 | | QST274BT | Blue mussel | AZA-1 | 218 | 180.8 | mg/kg | -1.3 | | QST274BT | Blue mussel | AZA-2 | 59 | 59.2 | mg/kg | 0.0 | | QST274BT | Blue mussel | AZA-3 | 49.6 | 50.9 | µg/kg | 0.2 | | QST274BT | Blue mussel | AZA-total | 392 | 358.5 | µg AZA eq./kg | -0.7 | | QST274BT | Blue mussel | Free-DTX2 | 297 | 284.7 | µg/kg | -0.3 | | QST274BT | Blue mussel | free-Okadaic Acid | 67.5 | 57.9 | µg/kg | -1.1 | | QST274BT | Blue mussel | Total-free-OA+DTX1+DTX2 | 250 | 228.7 | µg OA eq./kg | -0.6 | | QST274BT | Blue mussel | Total-DTX2 | 439 | 368.6 | µg/kg | -1.2 | | QST274BT | Blue mussel | Total-Okadaic Acid | 156 | 125.5 | µg/kg | -1.5 | | QST274BT | Blue mussel | Total-hy-OA+DTX1+DTX2 | 435 | 346.7 | µg OA eq./kg | -1.6 | | QST274BT | Blue mussel | Total OA group + PTX group | 433 | 346.7 | µg/kg | -1.5 | Overall Summary of Proficiency Tests

The proficiency tests for domoic acid were 100% satisfactory (8/8).

For PSP they were 84% satisfactory (31/37); both rounds of the Quasimeme tests were 100% satisfactory but for the EURL there were 5 questionable and 1 unsatisfactory z-scores. The EURL report indicated that there were some problems with the identification and quantification of dcNEO in sample 1 with only half of participants identifying it. The sample was homogenised clam tissue originating from Spain during an episode of Gymnodinium catenatum, the toxin profiles of which have previously been particularly problematic to determine. The EURL report provided z-scores for total toxicity with and without the contribution of dcNeo and without it our z-score was 0.4 (satisfactory). The z-scores with the contribution of dcNeo and all other analytes were z'-scores (z prime) indicating a degree of uncertainty for the assigned value. Analysis of samples 2 and 3 led to one questionable z-score for each. Sample 2 was a homogenate of mussels again displaying a typical Gymnodinium catenatum profile. For this sample only 35% of participants identified dcNeo and again the scores for all analytes were given as z'-scores. The failing z-scores were exclusively by overestimation of the assigned values and so may be attributed to the application of recovery correction creating falsely exaggerated results; this is not applied for the reporting of routine samples.

The lipophilic exercises were 99% satisfactory (94/95). There was a single questionable z-score (-2.1) in the EURL exercise for the hydrolysed OA result for sample 3 but the total toxicity was satisfactory as was the hydrolysed OA results for samples 1 and 2.

Internal non-conformance reports have been raised on our quality assurance system to address the discrepancies.

Overall performance for the three toxin groups in the three proficiency tests is 95% satisfactory (133/140), 4.3% questionable and 0.7% unsatisfactory.